The goal of the current project is to understand contextual and familial influences on adolescent stress hormone activity. Eighty mothers, fathers, and adolescents (240 participants) from two-parent working families will be recruited from an ongoing study of work family dynamics in which extensive information on individual functioning, family functioning, and extrafamilial context has been collected. For two weekdays, as they go about their daily lives, adolescent participants will wear wrist- watches that are programmed to beep 12 times during the day in six pairs of two beeps. At the first beep in each pair, participants will complete a structured diary entry reporting where they are, whom they are with, what they are doing, and what they are thinking and feeling. Twenty minutes later, the watch will beep again and participants will provide a sample of saliva to be assayed for cortisol. Participants will also report on their use of caffeine, nicotine, medications, exercise, hours of sleep, puberty, menstrual cycles, and on their physical and mental health. A hierarchical linear modeling (HLM) will be utilized to answer five-sets of questions: 1) How are cortisol levels related to the events, emotions adolescents' experience during the course of daily life? 2) What are the typical diurnal patterns of cortisol in adolescence and what degree of individual variability exists in them? 3) Do aspects in adolescent individual psychological functioning, family functioning, and their school and peer contacts mediate the links between events, emotions, and cortisol levels? 4) Do these aspects of adolescent functioning predict individual differences in the shapes of their diurnal cortisol curves? 5) Do parent and adolescent cortisol reactions to daily events and/or diurnal patterns of cortisol activity resemble one another? Sex differences in each of these examples will be examined. Individual differences in cortisol activity have been linked to a variety of mental and physical disorders. Understanding individual differences in, and influences on, cortisol activity in adolescents may provide information on how to promote their neuroendocrine, emotional, and physical health.